Resistance for electrical circuits.



No. 788,686. PATBNTED MAY 2, 1905.

' H. L. VAN VALKENBURG.

RESISTANCE FOR ELEGTRIGAL CIRCUITS.

APPLICATION FILED AUG. 6,1904.

' 2 SHEETS-SHEET 1.

INN

No. 788,686. PATENTED MAY 2, 1905.

' I H. L. VAN VALKENBURG.

RESISTANCE FOR ELECTRICAL CIRCUITS.

APPLICATION FILED AUG. 6,1904.

2 SHEETS-SHEET 2.

WITNESSES: INVENTOR 63' HM BY W mun EY UNITED STATES Patented May 2, 1905.

PATENT OFFICE.

HER ON i L. VAN VALKENBURG, OF PITTSBURe, PENNSYLVANIA, AS- SIGNOR To WESTINGHOUSE ELECTRIC & MANUFACTURING COM- PANY, A CORPORATION OP PENNSYLVANIA.

RESISTANCE FOR ELECTRICAL CIRCUITS- SPECIFIGATIQN forming part of Letters Patent No. 788,686, dated May 2, 1905.

Application filed August 6,1904. Serial No. 219,788.

T0 at whom it may concern:

Be it known that I, HERMON L. VAN VAL- KENBURG, a citizen of the United States, and a resident of Pittsburg, in the county of Al legheny and State of Pennsylvania, have invented a new and useful Improvement in Re sistances for Electrical Circuits, of which the following is a specification.

My invention relates to resistances for electrical circuits; and it has for its object to provide a resistance element and a combination of such elements which shall be simple and inexpensive in construction and durable and eflicient in operation.

With these ends in view I have devised the apparatus shown in the accompanying drawings, in which Figure 1 is a face view of a rheostat, a portion of the front plate of which is broken away to show the resistance elements. Fig. 2 is a sectional view of the rheostat or resistancebox shown in Fig. 1. Fig. 3 is a perspective view of an insulating-block, and Fig. 4 is a sectional View of two rheostat elements.

I have shown a set or series of resistance elements 1, mounted in a box or casing 2, the cover 3 of which is provided with stationary contact-terminals 4, arranged in the arc of a circle in order that the free end of a pivoted contact-arm 5 may make successive engagement therewith, this form of box and faceplate and the cooperating devices being such as are ordinarily employed in the art.

Each of the resistance elements 1 comprises a bar or rod 6, which may be of wrought-iron in the box, a strip or bar 10 of channel-iron being preferably utilized for this purpose.

By means of the arrangement and disposi tion of the insulating materials here shown and described the maximum, as well as the most economical protection, is afforded. The asbestos sheaths 7 serve to insulate the resistance-coils 8 from the bars 6, and it is only necessary that they have suflicient insulating strength to withstand the voltage due to the drop of potential in the coils which surround them. The blocks 9 serve to insulate the coils from each other and from the ground, and hence are made of porcelain or other good insulating material.

The several coils are suitably connected at their ends, as indicated at 11, and they are also connected at suitable intervals by means of leads 12 to the stationary contact-terminals 4 on the base-plate 2. In order to effectively insulate the leads 12 from each other and from the resistance-coils, they are severally provided with a set of beads 13, which may be of porcelain or other suitable insulating material and are strung loosely upon the leads, so that they constitute flexible but effective insulating-sheaths for the leads.

As I have indicated in Fig. 4, the connections between adjacent coils may be provided with insulating-beads 14, if desired, in order to effectively guard against any possible short circuits at such points.

The form of coils and supporting means therefor may obviously be widely varied within the scope of my invention, and it will be also feasible to utilize the invention in any and every relation where resistance in electrical circuits is desired for any purpose.

I claim as my invention- 1. The combination with a frame or casing, of a plurality of resistance elements each comprising a rod or bar. a sheath or covering therefor of insulating, heat-resisting material, a resistance-coil surrounding said sheath or covering and independent insulating-blocks having recesses in which the ends of said bar are seated.

2. A rheostat or resistance-box comprising a suitable frame or casing and a set of resistance elements severally consisting of iron rods, insulating, heat-resisting sheaths or coverings therefor, resistance-coils surrounding said sheaths or coverings and insulatingblocks having recesses to receive the ends of said bars and mounted in channels in said frame or casing.

3. A rheostat or resistance-box comprising a casing having a face-plate provided with contact-terminals, channel-bars at the opposite ends of said casing, insulating-blocks seated side by side in said channel-bars, rods having their ends seated in recesses in said insulating-blocks, insulating, heatresisting sheaths for said rods and helical resistancecoils surrounding said sheaths and electrically connected together and to the contact-terminals on the face-plate.

4. A rheostat or resistance-box having a frame or casing provided with a face-plate and with contact-terminals mounted thereon, a series of resistance elements each of which consists of an iron rod or bar, a sheath of insulating, heat-resisting material, a resistancecoil surrounding said sheath, and insulatingblocks having recesses in which the ends of the iron bars are seated, said resistance-coils being connected together and to the face-plate contact-terminals and having insulating-beads mounted upon the connecting-leads.

5. In a rheostat or resistance-box, the combination with a frame or casing, of a plurality of resistance elements each of which comprises a supporting rod or bar, a sheath of non-conducting, heat-resistingmaterial therefor, a coil of wire surrounding said sheath and independent insulating-blocks mounted in said frame or casing and having recesses in which the ends of the rod or bar are seated.

In testimony whereof I have hereunto subscribed my name this 29th day of July, 1904.

H. L. VAN VALKENBURG.

Witnesses:

R. A. L. SNYDER, BIRNEY Hnvus. 

